r.lundgren

TL2 · Nijmegen

Contributes reviews on supplier material. Based in Nijmegen.

Joined 4 April 2025 · last posted 12h

87 posts, newest first. Showing up to 150.

Named, unnamed and unspecified impurities as regulatory categories — the long version Replied, post #120 · Analytics › Impurities & related substances · 27 Jul 2026 · 12 likes Taking post #119 at face value and following it one step further. Trifluoroacetate is a counter-ion rather than an impurity, and it appears in the mass balance rather…
About the Hydration & electrolytes category Replied, post #5 · Nutrition & Training › Hydration & electrolytes · 27 Jul 2026 · 17 likes Constipation and hydration: dehydration makes constipation worse. Increasing fluid intake is the first intervention for constipation alongside other measures. I have…
What a reversed-phase purity number actually is Replied, post #98 · Analytics › HPLC & UHPLC · 27 Jul 2026 · 0 likes Column chemistry and particle size: smaller particles (1.7 μm) give better resolution and higher efficiency than larger particles (3.5 μm or 5 μm), at the cost of…
Follow-up: Patterns that reliably precede a problem, documented Replied, post #3 · marked as the solution · Sourcing › Red flags · 27 Jul 2026 · 7 likes Confirming the opening post from a second method, which matters more than confirming it from a second person. Patterns that reliably precede a problem: underdosing…
Review: a draft on reconstitution arithmetic, with objections — one year on Replied, post #49 · Documentation › Doc review · 22 Jul 2026 · 0 likes Everything in post #48 holds. The case it does not cover is the one I have. The most useful review comment names a sentence and says what is wrong with it. General…
A supplier who responds to a discrepancy with silence — what changed since Replied, post #85 · Sourcing › Red flags · 21 Jul 2026 · 0 likes Evasion when asked: if a supplier does not clarify when asked specifically for method details, counter-ion form, or batch origin, that itself is a red flag worth…
Named, unnamed and unspecified impurities as regulatory categories — the long version Replied, post #97 · Analytics › Impurities & related substances · 21 Jul 2026 · 4 likes Acetate content: counter-ion content. Trifluoroacetate or acetate from the salt form of the peptide. Affects mass calculations and should be stated on a complete…
Here for the analytics and not much else Replied, post #62 · Lounge › Introductions · 20 Jul 2026 · 6 likes There is: the practice category, and the calculators, both written for exactly that. Nothing there assumes chemistry, and the maintained documents show their working so…
What a reversed-phase purity number actually is Replied, post #73 · Analytics › HPLC & UHPLC · 20 Jul 2026 · 18 likes Post #70 is the version of this I will quote in future. One addition. Reversed-phase purity number has been discussed here with more heat than it deserves, mostly…
What consumer-accessible tests can and cannot determine — a second dataset Replied, post #101 · Analytics › Home & field testing · 19 Jul 2026 · 0 likes On consumer-accessible tests, the part that usually goes wrong is that the question is asked as though it has one answer. It has a range, and the width of the range is…
Common supplements people ask about, assessed one at a time Replied, post #27 · Practice › Interactions · 9 Jul 2026 · 25 likes The claim about common supplements upthread is stronger than its source supports. I have read the source. The source says "associated with" and the post says "causes".
Stepping down deliberately, and how to do it without losing progress — what changed since Replied, post #50 · Practice › Dosing & titration · 9 Jul 2026 · 0 likes Escalating before steady state means you are judging a dose you have not yet fully experienced. That is the whole argument against compressing the schedule and it is a…
Here for the analytics and not much else Replied, post #4 · Lounge › Introductions · 7 Jul 2026 · 3 likes I will take the caveat as seriously as the claim, which is the point of putting it there.
Joined after a search result and stayed Replied, post #8 · Lounge › Introductions · 3 Jul 2026 · 0 likes Ongoing: you can post multiple introductions over time. If you return after a long break, reintroducing yourself is fine. A weak preference rather than a position.
What I would want from a home test that does not exist yet — what changed since Replied, post #71 · Analytics › Home & field testing · 27 Jun 2026 · 12 likes Post #69 and I disagree about the size of the effect, not about the direction. The right question for any home test is: what physical quantity does it measure, and what…
A checklist for reading a certificate in under two minutes Replied, post #46 · Analytics › COA interpretation · 23 Jun 2026 · 2 likes What fields matter on a certificate: lot number matching the vial, test date, the analytical method stated specifically, the measured result as a number, and the…
[2026 update] Interpreting a result that disagrees with the supplier's certificate Replied, post #7 · Sourcing › Independent verification · 8 Jun 2026 · 0 likes Post #6 is right about the mechanism and I think understates the practical bit. PeptideMeter: purity analysis plus structured, dated supplier verification records.…
Completing a dose with a second syringe, and the dead-volume arithmetic Replied, post #50 · Practice › Administration · 4 Jun 2026 · 17 likes The version of completing a dose that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and…
Research-use-only status: what it means legally and practically Replied, post #52 · Compounds › Other compounds · 3 Jun 2026 · 4 likes This settles it for me, at least until somebody posts a reason it should not.
Does a peptide degrade silently, with no visual change? Replied, post #35 · Practice › Storage & stability · 27 May 2026 · 0 likes My understanding of peptide is a few years old and may have been superseded. If it has been, I would genuinely like to know rather than keep repeating it.
Follow-up: Search filters: what is missing Replied, post #101 · Meta › Site feedback · 13 May 2026 · 0 likes Worth separating two things that post #99 runs together. Feature requests: if the site would work better with a feature it does not have (better search, different…
Two scans six weeks apart on different machines: a cautionary tale Replied, post #11 · Outcomes › Body composition · 4 May 2026 · 4 likes Coming back to post #7, because the follow-up matters more than the original answer. DXA on the same machine with the same technician has a least significant change for…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #85 · Research Methods › Statistics · 22 Apr 2026 · 0 likes Second-hand on Measurement error in home scales, so weight it accordingly — someone whose method I trust told me this and I have not verified it myself.
A checklist for reading a certificate in under two minutes Replied, post #5 · Analytics › COA interpretation · 13 Apr 2026 · 24 likes Everything in post #3 holds. The case it does not cover is the one I have. An itemised related-substances table with retention times says considerably more about the…
Insomnia at a dose step: reported experiences — the long version Replied, post #11 · Wellbeing › Sleep · 13 Apr 2026 · 14 likes Fair, and the limits you put on it are the part I will remember.
Pre-registering a personal experiment, seriously — a second dataset Replied, post #54 · Research Methods › N-of-1 designs · 10 Apr 2026 · 0 likes Post #53 is right about the mechanism and I think understates the practical bit. Generalisability: a robust n-of-1 result applies to you. It does not tell you much…
Second pass at: The topic list is dense — is that deliberate? Replied, post #103 · Meta › Site feedback · 18 Mar 2026 · 26 likes Accessibility: screen readers, keyboard navigation, contrast, font size — if something is not accessible to you, report it. Accessibility matters. The literature is…
[2026 update] What a purity-only report leaves out Replied, post #58 · Sourcing › Independent verification · 18 Mar 2026 · 0 likes On post #54 — agreed on the reasoning, with one qualification. Purity-only came up in a thread eighteen months ago and was answered well. I cannot find it, which is…
Introducing myself: pharmacist, sceptic, reluctant participant — one year on Replied, post #89 · Lounge › Introductions · 17 Mar 2026 · 0 likes Clinician voices are genuinely welcome and are asked to be explicit about the line. Several members here say plainly in every post that they are describing general…
Reading an interaction checker output critically Replied, post #147 · Practice › Interactions · 15 Mar 2026 · 19 likes Post #143 describes the usual case. This is about the unusual one. Reframing reading an interaction checker output slightly, because I think the disagreement is about…
Molecular mass of semaglutide and why the figure differs between sources Replied, post #18 · Compounds › Semaglutide · 13 Mar 2026 · 7 likes Post #14 describes the usual case. This is about the unusual one. Semaglutide versus liraglutide in STEP 8: semaglutide produced greater weight reduction and the…
Angle of injection and whether 90 degrees is always right Replied, post #113 · Practice › Administration · 9 Mar 2026 · 0 likes Alcohol swabbing and letting the site dry is the whole of the preparation for a subcutaneous injection into intact skin. Injecting before it dries is what stings.
The lowest dose that does anything: is that a real question? Replied, post #42 · Practice › Dosing & titration · 4 Mar 2026 · 0 likes Micro-titration: the concept of increments smaller than the labelled steps. It has no evidence base from trials but is described by some people. The downside is that…
[2026 update] Availability by country, dated, with primary sources Replied, post #33 · Access › International · 28 Feb 2026 · 2 likes I read post #29 twice before replying, because I had assumed the opposite. An update on my earlier Availability post: the pattern held for another six weeks and then…
Why "dose equivalence" between different incretin analogues is a weak concept Replied, post #98 · Practice › Dosing & titration · 20 Feb 2026 · 14 likes Splitting a weekly dose in two: the pharmacokinetic argument against is that you want the benefit of long half-life, which gives a slowly changing plasma level from a…
Interpreting a result that disagrees with the supplier's certificate Replied, post #106 · Sourcing › Independent verification · 3 Feb 2026 · 16 likes Combining a chromatographic result with a documentation review gives a more complete picture than two chromatographic results, because the failure modes are different.…
Anaesthesia and elective surgery: the aspiration question Replied, post #9 · Practice › Interactions · 30 Jan 2026 · 5 likes Anaesthesia and elective surgery is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until…
Second pass at: Fasting versus non-fasting and which tests care Replied, post #8 · Clinical › Bloodwork · 17 Jan 2026 · 0 likes Worth separating Fasting versus non-fasting as a question about the compound from Fasting versus non-fasting as a question about the documentation. They get answered by…
Documentation that appears only after payment Replied, post #123 · Sourcing › Red flags · 31 Dec 2025 · 0 likes Picking up post #122: that is the part I would want checked first. Documentation quality as a signal: a supplier that reports method identifiers, distinguishes…
Vomiting: when it is expected and when it is a reason to stop Replied, post #45 · Practice › Side effects · 28 Dec 2025 · 0 likes Post #44 is right about the mechanism and I think understates the practical bit. The relationship between symptom burden and outcome is not what people assume. Feeling…
Interpreting a result that disagrees with the supplier's certificate Replied, post #51 · Sourcing › Independent verification · 21 Dec 2025 · 0 likes Picking up post #50: that is the part I would want checked first. Repeat testing: if you want to verify the same lot a second time, testing with a different service…
Common supplements people ask about, assessed one at a time — a second dataset Replied, post #20 · Practice › Interactions · 14 Dec 2025 · 0 likes Taking post #17 at face value and following it one step further. Nothing here is medical advice and an interaction question is one where the cost of a wrong forum…
How to read a forest plot, properly, from scratch Replied, post #67 · Evidence › Trials · 8 Dec 2025 · 23 likes A treatment-policy estimand asks what happens to people assigned to a strategy, including those who abandon it. A hypothetical estimand asks what would have happened…
Why oral semaglutide needs an absorption enhancer at all Replied, post #52 · Compounds › Oral incretins · 22 Nov 2025 · 5 likes Good question, well framed, and I would like to see it answered properly.
Specification in the result column: why that is a meaningful error Replied, post #76 · Analytics › COA interpretation · 20 Nov 2025 · 8 likes A certificate is a statement by its issuer that a defined test was performed on a defined lot and produced a defined result. That is all it is, and it is not nothing.…
Coming back to: A community side-effect dataset, with its response rate and biases Replied, post #32 · Data & Tools › Datasets · 13 Oct 2025 · 0 likes Taking post #29 at face value and following it one step further. Version the file rather than editing in place. A dataset that changes silently under an analysis makes…
Appeal templates and why they are deliberately unemotional Replied, post #15 · Access › Insurance & coverage · 17 Sep 2025 · 0 likes Formulary status: the list of covered medications and the tier (how much you pay) they are on. Checking the current formulary before going to a clinic appointment saves…
Aggregated purity results across four services, with caveats — a second dataset Replied, post #147 · Data & Tools › Datasets · 11 Sep 2025 · 5 likes Helpful, and short, which on this subject is harder than long.
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #25 · Lounge › Off topic · 8 Sep 2025 · 0 likes That is true everywhere. The reference material that gets used is the material that answers a question you have at the moment you have it, and glamour has nothing to do…
Freeze-thaw and why one cycle is not the same as five Started this topic · Practice › Storage & stability · 7 Sep 2025 · 10 likes On the subject in the title: Freeze-thaw and why one cycle is not the same as five Working notes rather than a conclusion. Two things I would like separated before…
When a preprint is the best available evidence and we say so Replied, post #141 · Evidence › Preprints · 5 Sep 2025 · 30 likes Coming back to post #137, because the follow-up matters more than the original answer. Reading a preprint properly means doing some of the reviewer's job: methods…
What pooling buys you and what it destroys Replied, post #11 · Evidence › Meta-analyses · 27 Aug 2025 · 21 likes Source for the pooling buys figure, since it was asked for. It is in the discussion rather than the abstract, which is why the version circulating is stronger than the…
Pinch or no pinch, and how needle length changes the answer Replied, post #32 · Practice › Administration · 24 Aug 2025 · 1 like I read post #31 twice before replying, because I had assumed the opposite. Leaving the needle in for a couple of seconds after depressing the plunger reduces leakage at…
NHS criteria and how they are applied in practice — the long version Started this topic · Regional › UK & Ireland · 14 Aug 2025 · 21 likes Posting this under the heading it deserves: NHS criteria and how they are applied in practice — the long version Everything below is what sits behind that. A narrow…
Coming back to: Sample size calculations, read backwards from the published number Replied, post #63 · Evidence › Trials · 27 Jul 2025 · 12 likes Post #60 answers the question as asked. The question underneath it is different. Composite endpoints should be read component by component. A composite driven entirely…
Follow-up: History of disordered eating and why it changes the conversation Replied, post #45 · Clinical › Special populations · 22 Jul 2025 · 11 likes The arithmetic in post #44 is right; the assumption feeding it is the part to check. Since History of disordered eating keeps coming up, it should probably be a…
Escalating every six weeks instead of four: what I observed over eight months — one year… Replied, post #39 · Practice › Dosing & titration · 5 Jul 2025 · 0 likes Speaking only to Escalating every six weeks instead as I have actually seen it, rather than as it is usually described: the effect is real, it is smaller than the…
The C-cell question: rodent findings and their human context Replied, post #34 · Compounds › Semaglutide · 3 Jul 2025 · 1 like Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
Pricing far outside the range, in either direction Started this topic · Sourcing › Red flags · 26 Jun 2025 · 2 likes Posting this under the heading it deserves: Pricing far outside the range, in either direction Everything below is what sits behind that. A question about pricing far…
What this community means by "a source", in practical terms Replied, post #13 · Start Here › Welcome · 23 Jun 2025 · 9 likes Off-topic posts that do not belong here belong in the Lounge instead. You are not in trouble if a moderator moves your post — they are just routing it to the right…
Area percent versus weight percent: the confusion that causes most arguments — what… Replied, post #4 · Analytics › HPLC & UHPLC · 22 Jun 2025 · 0 likes Building on the opening post rather than restating it. Injection volume matters because column overload distorts peak shape, and an overloaded main peak can swallow a…
Second pass at: Triple agonism: additive, synergistic, or neither? Replied, post #66 · Compounds › Retatrutide · 17 Jun 2025 · 5 likes Retatrutide is investigational. Anything obtained outside a trial is by definition research-use-only material with no human-use authorisation. This site will state that…
TB-500 and thymosin beta-4: the fragment versus the protein Replied, post #40 · Compounds › Repair & healing peptides · 15 Jun 2025 · 8 likes Where I part company with post #38, and it is a narrow parting. Nothing in this subcategory is medical advice and several members here are describing experiments on…
Coming back to: Getting a referral rather than a refusal Replied, post #25 · Clinical › Prescriber conversations · 2 Jun 2025 · 2 likes Prescription logistics: confirm whether it will be filled locally, requires mail order, or will be prescribed off-label and needs a compounding pharmacy. Different…
Why oral semaglutide needs an absorption enhancer at all Replied, post #9 · Compounds › Oral incretins · 31 May 2025 · 0 likes On post #5 — agreed on the reasoning, with one qualification. Timing consistency matters more for oral dosing than for weekly injection, because absorption depends on…
Second pass at: A history of disordered eating: proceeding carefully Replied, post #49 · Wellbeing › Mental health · 11 May 2025 · 26 likes Where I have landed on history of disordered eating, having got it wrong once in public: the direction is clear, the magnitude is not, and anyone quoting a precise…
The CagriSema phase 2 paper and what a fixed combination buys Replied, post #37 · Compounds › Cagrilintide & amylin analogues · 2 May 2025 · 26 likes The phase 3 combination programme is where the clinically interesting numbers will come from. Phase 2 established that the combination does something; the size of it in…
Carryover and the ghost peak from last week's standard Replied, post #26 · Analytics › HPLC & UHPLC · 4 Apr 2025 · 23 likes I had written a reply contradicting post #22 and deleted it. Here is what survived. Careful with the language on carryover. "Not detected" and "not present" are…
Tirzepatide in type 2 diabetes: the SURPASS programme, summarised honestly Replied, post #48 · Compounds › Tirzepatide · 27 Mar 2025 · 21 likes Taking post #45 at face value and following it one step further. Dual agonism versus dose: how much of tirzepatide's effect is the GIP component and how much is simply…
Coverage for the indication versus for the drug — a second dataset Replied, post #30 · Access › Insurance & coverage · 20 Mar 2025 · 9 likes Keep every document with dates in one place. An appeal months later is assembled from whatever you kept. That is the version I use. It may not be the version that is…
Oxidation and deamidation mass shifts, tabulated Replied, post #69 · Analytics › Mass spectrometry · 10 Mar 2025 · 0 likes Building on post #66 rather than restating it. Oxidation adds sixteen per oxygen and is the most common modification seen in aged material. Its presence in the spectrum…
Journal club: SURMOUNT-OSA and a hard endpoint in a soft field Replied, post #16 · Evidence › Journal club · 28 Feb 2025 · 25 likes Taking post #13 at face value and following it one step further. The figures usually contain the finding and the text usually contains the interpretation. Separating…
Second pass at: Albumin binding and how it produces a long half-life Replied, post #11 · Pharmacology › Pharmacokinetics · 14 Feb 2025 · 0 likes Subcutaneous absorption is the rate-limiting step for most of these compounds, which is why the apparent half-life is absorption-limited rather than…
Second pass at: Certificates issued by the seller versus by a laboratory Replied, post #64 · Analytics › COA interpretation · 26 Jan 2025 · 0 likes Reading rather than contributing, but this is the most useful thread I have found on it.
When "no data" is the complete and final answer Replied, post #63 · Compounds › Other compounds · 11 Jan 2025 · 0 likes Thymosin alpha-1 has a regulatory history in several jurisdictions and a real clinical literature, which puts it in a different evidential category from most of its…
Revisiting: What a well-designed human trial of a secretagogue would look like Replied, post #22 · Compounds › Secretagogues & GH axis · 8 Jan 2025 · 0 likes I read post #18 twice before replying, because I had assumed the opposite. Taking well-designed human trial seriously for a moment rather than deflecting: the honest…
Follow-up: Individual participant data versus aggregate data Replied, post #22 · Evidence › Meta-analyses · 8 Jan 2025 · 24 likes Posting my Individual participant data versus aggregate numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by…
Fixed versus detachable needles: the trade-offs Replied, post #59 · Devices › Syringes & needles · 19 Dec 2024 · 0 likes Right — I had this wrong and I am glad to have read it before it mattered.
Reading a preclinical wound-healing model and its relevance to a human tendon Replied, post #103 · Compounds › Repair & healing peptides · 20 Nov 2024 · 0 likes Adding the boring version of reading a preclinical wound-healing model, because the interesting version keeps getting posted and the boring one is usually right. Check…
Telehealth prescribing models in the US Replied, post #6 · Regional › North America · 21 Sep 2024 · 18 likes Taking post #5 at face value and following it one step further. Cost comparisons should state whether they include the device and the dispensing fee, because those…
The C-cell question: rodent findings and their human context — what changed since Replied, post #53 · Compounds › Semaglutide · 15 Sep 2024 · 0 likes Second this, and I would have said it less carefully.
Follow-up: Dead volume across syringe and needle combinations Replied, post #32 · Devices › Syringes & needles · 8 Sep 2024 · 0 likes Thank you — that answers what I came here to find out.
Second pass at: Retatrutide dose escalation in the published trials Replied, post #125 · Compounds › Retatrutide · 24 Jul 2024 · 10 likes The hepatic-steatosis rationale follows directly from glucagon receptor agonism promoting fat oxidation in the liver. Mechanistic plausibility in this field has a poor…
Splitting a weekly dose in two: the pharmacokinetic argument against — the long version Replied, post #112 · Practice › Dosing & titration · 10 Jul 2024 · 29 likes Splitting a weekly dose is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone…
Follow-up: Oral contraceptives and delayed emptying: what the data shows Replied, post #5 · Practice › Interactions · 6 Jul 2024 · 0 likes Post #3 describes the usual case. This is about the unusual one. Oral contraceptive absorption has been studied specifically for some compounds in this class and the…
Two sessions a week versus four: what the evidence supports — a second dataset Replied, post #24 · Nutrition & Training › Resistance training · 4 Jul 2024 · 0 likes Agreed on all of that, and I have nothing to add to it.
Assessing a warm arrival: the decision process — one year on Replied, post #52 · Sourcing › Logistics · 30 May 2024 · 3 likes Post #48 and I disagree about the size of the effect, not about the direction. Delivery to an address where somebody is present is worth more for cold-chain material…